Terminal assembly



April 16, 1963 T. c. PRICE 3,086,194

TERMINAL ASSEMBLY Filed Sept. 12, 1960 INVENTOR. 2 THOMAS (1. PR E AGENT United States Patent 3,086,194 TERMINAL ASSEMBLY Thomas C. Price,Monroe, Conn., assignor to Burndy Corporation, a corporation of New YorkFiled Sept. 12, 1960, Ser. No. 55,296 1 Claim. (Cl. 339-272) Thisinvention relates to terminals for conductors; and more particularly topressure bars for attachment to setscrews for lug type terminals.

Lug type terminals have long been used in the electrical arts. Theyconsist essentially of a socket, or similar means to receive aconductor, and a lug, tongue, spade or similar projection for attachmentof the terminal to the article to which the conductor is to beconnected. The lug may have a hole therethrough to receive a bolt, sothat the terminal may be bolted to the article. The conductor may besecured in the terminal socket by various means, such as a setscrew,crimping, soldering or welding. The function of the setscrew is to forcethe conductor into good mechanical and electrical contact with the innerwall of the socket opposite the setscrew.

It is customary in the art to provide an intermediate member to transmitthe force of the setscrew to the conductor. This intermediate member, orpressure bar, is commonly captured by the setscrew and may be designedto rotate relative to the setscrew. This should permit the pressure barto remain stationary relative to the surface of the conductor andthereby not score, dig into, or otherwise damage the conductor surface;while permitting the setscrew to rotate relative to the pressure bar sothat it may be screwed into the connector housing to apply pressure tothe conductor. The pressure bar may also be made of resilient materialwhich may be deformed under pressure; this tends to maintain a uniformpressure on the conductor, even though the relative dimensions of theconductor and terminal may have changed under continuous load.

.The prior art devices generally suffer from several disadvantages. Thepressure bar is usually staked or permanently deformed and captured tothe set screw, requiring a separate machine operation for this purpose.If the pressure bar is larger than the setscrew hole, this operationmust be performed after the setscrew has been inserted in the connector.Often, the pressure bar does turn with the setscrew, damaging thesurface of the conductor.

An object of this invention, therefore, is to provide a pressure barwhich may be easily attached to the setscrew before the setscrew hasbeen assembled into the terminal.

Another object of this invention is -to provide a pressure bar whereinthe pressure bar setscrew interface may be lubricated to ensure freerelative motion therebetween.

Yet another object is to provide a resilient pressure bar which may bedeformed under load to provide a constant pressure on the conductor.

A further object is to provide a pressure bar which may be cheaplyfabricated of sheet metal.

These and other objects and features of this invention will become moreapparent by reference to the following description taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a lug terminal, setscrew andpressure bar embodying this invention; and

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FIG. 2 is a cross section taken through the pressure bar of FIG. 1 alongline IIII, and including a portion of the setscrew assembled thereto.

FIG. 1 illustrates a terminal assembly including a terminal body 1having a conductor receiving socket 2, lug 3 and a threaded hole 4 inthe socket wall providing access to the socket. A setscrew 5 is disposedin hole 4 and a conductor (not shown) may be disposed in socket 2.Setscrew 5 is provided with annular groove 6 adjacent its force applyingend. A sheet metal, cup shaped, pressure bar 7 having a plurality ofresilient fingers 8 may be snapped onto the end of the screw, an inwardgoing bend 9 in each finger 8 engaging the groove 6.

As may also be seen in FIG. 2, the base of the bar 7 may be indented toprovide a plurality of radial projections 10. Projections 10 are adaptedto engage the surface of the conductor, and prevent the bar 7 fromrotating on the surface of the conductor. The projections 10 are alsoadapted to resiliently deform under load; thereby maintaining a constantpressure on the conductor even though the conductor may tend to deformunder load.

Being cup shaped, the bar 7 is especially adapted to receive therein alubricant, such as a graphite powder, and thereby maintain a lubricatedinterface between the bar 7 and the setscrew 5 having minimum frictiontherebetween. The bar 7, being held to the screw 5 solely by itsresilient fingers 8, may be easily removed and replaced on the screw 5for lubrication purposes. This arrangement ensures that the bar 7 willnot rotate with respect to the conductor surface, but will rotate withrespect to the setscrew 5, as the screw is tightened against theconductor.

The pressure bar 7 may easily and cheaply be formed out of sheet metalstock. The annular groove 6 on the end of the setscrew 5 may be machinedbelow the base of the thread, thereby permitting the use of a pressurebar smaller in diameter than the bolt; which may be snapped onto thesetscrew before it is assembled into the connector; the subassembly ofscrew 5 and bar 7 then being screwed into hole 4.

The invention has thus been described but it is desired to be understoodthat it is not confined to the particular forms or usages shown anddescribed. The same being merely illustrative, and that the inventionmay be carried out in other ways without departing from the spirit ofthe invention, and therefore, the right is broadly claimed to employ allequivalent instrumentalities coming within the scope of the appendentclaims, and by means of which objects of this invention are attained andnew results accomplished, as it is obvious that the particularembodiments herein shown and described are only some of the many thatcan be employed to obtain these objects and accomplish these results.

I claim:

A terminal assembly for a conductor comprising: a body having aconductor receiving socket therein; a threaded hole included in the wallof said body giving access to said socket; a setscrew disposed in saidthreaded hole and adapted to project into said socket, an end portion onsaid screw having a surface for applying pressure to an abuttingsurface, an annular groove on said screw adjacent said end portion; acup shaped intermediate member adapted to transmit pressure from saidend portion to the surface of an inserted conductor; said cup enclosingsaid end portion and having a plurality of resilient 3 fingers adaptedto engage said groove; said cup including a plurality of resilientprojections adapted to engage the surface of the inserted conductor andthereby fix said cup to the conductor surface; said cup being free torotate with respect to said setscrew.

References Cited in the file of this patent UNITED STATES PATENTS1,275,961 Maynard Aug. 13, 1918 Great Britain Feb. 23, 1901

